JP4945661B2 - Micro diaphragm pump - Google Patents

Description

  The present invention relates to a micro-diaphragm pump formed by laminating and joining a plurality of thin metal plates having patterns such as a valve plate, a valve seat, and a diaphragm.

In recent years, the spread and commercialization of fuel cell systems are expected as a distributed energy plant for home use (for detached houses). This type of fuel cell requires a pump for supplying fuel gas, liquid fuel, water supplied to the reformer, hydrogen produced by the reformer, and the like to the fuel cell itself. Carbon monoxide (CO) is produced during reforming to extract the necessary hydrogen (H ₂ ) from the fuel. This carbon monoxide adversely affects the performance of the battery catalyst, so it is selected to reduce the carbon monoxide concentration. Control of the flow rate of oxidizing air is also required at the same time. Furthermore, analytical devices and medical care (medicine, clinical trials, etc.) require the supply of very small amounts of gas or liquid. Furthermore, a pump for releasing and cooling the heat generated with the performance improvement of the electronic device is also required.

  Conventionally, various micropumps used for such applications have been proposed. In Patent Document 1, an inflow valve and an outflow valve (6, 6) sandwiching a valve body (10) between a metal outbush (first column part 13) and an inbush (second column part 16) are disclosed. A micropump 1 in which 7) is arranged so as to be orthogonal to a flat pressure chamber 2 provided in the pump body is disclosed. Here, the diaphragm 8 forming the pressure chamber 2 is disposed so as to cover the inlet and outlet of the two valves 6 and 7.

  In Patent Documents 2 to 5, a pressure chamber (diaphragm chamber) is provided between the suction valve and the discharge valve, and the pressure chamber pressure is changed by a piezo element attached to the diaphragm defining the pressure chamber. A pump that discharges is shown. That is, the diaphragm does not cover the suction valve and the discharge valve (is in contact with one side surface of both valves). In addition, a silicon substrate is partially used.

JP 2009-236284 A Japanese Patent Laid-Open No. 2006-161779 JP-A-6-93972 JP-A-5-1669 JP 10-299659 A

  In the one disclosed in Patent Document 1, since the suction valve and the discharge valve are two metal cylindrical members that are coaxially fitted and combined, the direction perpendicular to the diaphragm (the flow path between the suction valve and the discharge valve) Direction) is large, and it is difficult to reduce the size. Further, there is a problem that a lot of man-hours are required for processing and assembling of the cylindrical member, and productivity is poor. Furthermore, a relatively long fluid flow path is required between the pressure chamber and the valve body of each valve, and this flow path is substantially a part of the pressure chamber. Is a portion (unnecessary volume) where the fluid stays, the fluid flow rate control accuracy decreases.

  In all of Patent Documents 2 to 5, the diaphragm forming the pressure chamber is limited between the inflow valve and the discharge valve, and the area of the diaphragm is reduced. For this reason, the volume change of the pressure chamber due to the vibration of the diaphragm becomes small, and it is difficult to smoothly perform the fluid suction / discharge operation, and there is a problem that the discharge amount management for each stroke of the diaphragm becomes inaccurate. For this reason, it is difficult or impossible to use for compressible gas. Further, since the area of the diaphragm is small, there is a problem that it is difficult to increase the suction force and the discharge force of the fluid. Furthermore, there is a problem that the silicon substrate used here is relatively expensive.

    The present invention has been made in view of such circumstances, and can greatly reduce the outer dimensions, improve the productivity, improve the fluid flow rate control accuracy, and smooth the fluid suction / discharge operation, An object of the present invention is to provide a highly reliable micro-diaphragm pump that can increase suction force and discharge force, increase the degree of freedom in material selection without being restricted to a silicon substrate.

  According to the present invention, a first object is a micro-diaphragm pump having a diaphragm chamber that is in contact with one side of an intake valve and a discharge valve, wherein one of the valve plates of the intake valve and the discharge valve and a flow path of the other valve And two valve plate sheets laminated in a direction in which the valve plate and the flow channel opening face each other, and the valve of the one valve plate sheet laminated on both surfaces of the laminated body Two valve seat seats formed with a valve seat facing the plate and a valve stopper facing the valve plate of the other valve plate seat, and superimposed on one valve seat seat and communicated with the intake valve and the discharge valve, respectively A base plate having two flow paths, a frame that is superimposed on the periphery of the other valve seat and surrounds the suction valve and the discharge valve, and a valve seat that is superimposed on the frame and overlaps the frame A diaphragm that forms a diaphragm chamber between them , Micro diaphragm pump, characterized in that it comprises a drive element which is held in the diaphragm is accomplished by.

  According to the present invention, the area of the diaphragm can be expanded to the outside of the suction valve and the discharge valve. Therefore, the volume change of the diaphragm chamber can be increased to smoothly perform the fluid suction / discharge operation. Further, since the suction valve and the discharge valve are formed by overlapping two valve plate sheets and overlapping the valve seat sheets on both outer sides thereof, the whole can be made extremely thin and the pump can be miniaturized. Since the valve plate sheet, valve seat sheet, base plate, frame, and diaphragm are laminated and joined (multilayered joining), and the drive element can be attached to the diaphragm from the outside, productivity is high and significant cost reductions are possible. is there.

  Here, the valve plate seat and the valve seat can be stacked in the opposite direction if the combination of the two sheets constituting the intake valve and the combination of the two sheets constituting the discharge valve have the same shape. Therefore, in this case, the productivity is further improved. In particular, a plurality of pumps are formed simultaneously by preparing sheet-like members each formed with a valve plate sheet, valve seat sheet, base plate, frame, and diaphragm corresponding to a plurality of pumps, and laminating and joining them. Then, it is possible to cut the laminated body and divide it into individual pumps. In this case, the productivity is further improved.

  Since the diaphragm chamber (pressure chamber) and each valve are in contact with each other through one valve seat, the fluid flow path connecting the diaphragm chamber and each valve is extremely short, and the diaphragm is used when the diaphragm discharges fluid. The chamber volume can be made sufficiently small. That is, the ratio of (maximum volume / unnecessary volume) can be extremely increased. Therefore, the suction / discharge operation can be surely performed for each stroke of the diaphragm, and the management of the fluid discharge amount (flow rate) becomes accurate. Further, since the diaphragm area is large, the suction / discharge force of the fluid can be increased, and there is a possibility that it can be used not only for incompressible fluid (liquid etc.) but also for compressible fluid (gas etc.).

The perspective view of the micro diaphragm pump which is one Example of this invention Similarly exploded perspective view Also enlarged side sectional view A partially enlarged exploded perspective view Similarly, a plan view of the valve plate of the valve plate seat and the flow path opening Similarly, plan view of valve seat and valve stopper of valve seat VII-VII line enlarged sectional view in FIG. Side sectional view of the laminate taken along line VIII-VIII in FIG.

  The two valve plate sheets and the two valve seat sheets are formed of a thin metal plate such as stainless steel, and if they are joined in multiple layers, there is no need to use a relatively expensive silicon substrate. ). It is recommended to select a metal that will not corrode the fluid. In addition, in order to laminate and bond thin stainless plates, solder with a high Sn (tin) concentration or silver alloy solder plating such as Sn-Ag is used in terms of wettability and soldering strength to stainless steel. Various methods such as adhesives and metal diffusion bonding can be used.

  The valve plate is structured to be held by a support arm extending from the inner edge of the valve plate opening formed in the valve plate sheet to the inner diameter side, and becomes a flow path opening formed in the valve plate sheet and a flow path of the discharge valve formed in the base plate. The opening diameter of the flow path opening is preferably equal to (including substantially equal to or substantially equal to) the inner diameter of the valve plate opening (Claim 3). When multi-layer bonding of valve plate seats or valve seats, it is necessary to stack and pressurize, but at this time no pressure is applied to the valve plate or its support arm, and these are joined to other sheets. Can be prevented.

  The valve plate sheet and the valve seat sheet can be processed by various methods such as etching and press punching. In particular, when a large number of pump valve plates, flow passage openings, valve seats, valve stoppers, and the like are processed on these sheets, and a large number of pumps are manufactured at the same time, these sheets can be manufactured efficiently.

  The frame and the diaphragm are made of thin metal plates, which are laminated on one side of the laminate formed in claim 2 (preliminary laminate), and a base plate is laminated on the other side of the laminate to join the pump. Can be formed (Claim 5). As described above, the assembly accuracy can be improved and the production efficiency can be improved by dividing the lamination of the valve plate sheet and the valve seat sheet and the lamination of the frame body, the diaphragm, and the base plate into two joints.

  The valve seat formed on the two valve seats may be formed with an annular ridge that contacts the valve plate (Claim 6). This protrusion can be formed by leaving a portion that becomes a valve seat and slightly carving the periphery by half etching, but it may be formed by other methods. In this case, the contact pressure with respect to the protrusion of the valve plate is increased, and the sealing performance is improved. That is, the sealing performance as a valve is improved.

In this case, it is preferable to form a DLC (Diamond-Like Carbon ) film on the annular protrusion (claim 7). DLC includes a carbon structure with a good molecular structure and a diamond structure with a high hardness, and has the advantages of both. Therefore, the protrusion can be hardened and smoothed, and the wear resistance and durability are improved, and the sealing performance is improved. When DLC processing is performed on the ridges in this way, the adhesion between the valve plate and the valve seat is further improved by stamping (pressing) the valve plate onto the ridges by utilizing the high hardness of DLC. (Claim 8). In order to make this stamping possible, an opening through which a processing tool (such as a punch) for stamping is passed is formed in the valve stopper (claim 9). In other words, the valve stopper is provided with an annular portion facing the ridge serving as the valve seat (and thus facing the valve plate) and a circumferentially divided flow path around the annular portion, and a stamping tool is inserted into the annular portion. That's fine.

  A piezo element is suitable for the driving element held in the diaphragm. For example, it is possible to use a sintered body of a piezoelectric material that includes zircon / lead titanate (PZT) and is collectively called PZT, which is bonded to a diaphragm and polarized by applying an electric field. If the second frame surrounding the drive element is fixed to the diaphragm, the movable area (movable space) of the drive element and the diaphragm can be secured inside the second frame, and the pump is mounted on a substrate or the like. When mounted on, the adjacent parts do not come into contact with each other and the pump operation is not hindered.

  1-4, the code | symbol 10 is the micro diaphragm pump which concerns on this invention. The pump 10 is a multi-layered joining of a plurality of thin metal plates made of stainless steel and a frame, that is, a metal thin plate or the like is aligned and laminated, and is a quadrangle having a side of about 7 to 10 mm. Reference numeral 12 denotes a valve plate sheet. As shown in FIG. 5, a valve plate 14 and a channel opening 16 are formed by etching or press punching on a stainless steel plate having a thickness of 0.01 mm (10 microns). Here, the valve plate 14 is held by a support arm 14b extending from the valve plate opening 14a having substantially the same diameter as the flow path opening 16 while being bent toward the inner diameter side.

Reference numeral 18 denotes a valve seat. As shown in FIG. 6, a valve seat 20 and a valve stopper 22 are formed on a stainless steel thin plate by etching or press punching. The valve seat 20 has a circular opening 20a serving as a flow path and an annular protrusion 20b along the periphery. As shown in FIG. 7, the ridge 20b can be formed by slightly denting the ridge 20b while leaving the ridge 20b half-etched (removed to a predetermined depth by etching). In FIG. 7, reference numeral 20c denotes a range to be half-etched. Half-etching is performed in the range of the same diameter as the channel opening 16 from the center of the opening 20a.

  The valve stopper 22 includes an annular portion 22a that is wider than the protrusion 20b and three flow paths 22b that are divided in the circumferential direction around the annular portion 22a. The annular portion 22a is opposed to the protrusion 20b of the valve seat 20 through the valve plate 14 in a state where the pump 10 is assembled as will be described later. Further, the circular opening 22c of the annular portion 22a has a slightly larger diameter than the protrusion 20b because it needs to pass a stamping tool as will be described later.

  The valve plate sheet 12 and the valve seat sheet 18 processed in this way are prepared two by two, the valve plate sheets 12 and 12 are stacked as shown in FIGS. 2 to 4, and the valve seat sheets 18 and 18 are placed on both sides thereof. Multi-layer joining is performed. For example, diffusion bonding (bonding by heating and pressing in vacuum) is performed. At this time, as is clear from FIGS. 2 and 4, the valve plate sheets 12 and 12 are stacked with the left and right sides reversed (turned 180 degrees) or turned over. For this reason, the valve plate 14 and the flow path opening 16 of the valve plate sheet 12 are formed at positions that overlap with the valve seat 20 and the valve stopper 22 of the valve seat 18 when the left and right sides of the valve plate sheet 12 are reversed or turned over. . As a result, the laminated body (preliminary laminated body) 24 is formed with the suction valve 26 and the discharge valve 28 shown in FIG.

  A DLC film is formed on the protrusion 20b. The DLC can be formed, for example, by a physical method (PVD) such as vacuum deposition or sputtering, or a chemical method (vapor phase growth method) such as plasma CVD. At this time, masking for preventing the formation of a film is performed in the region other than the protrusions 20b. Further, when the half etching 20c is performed, masking for preventing etching is performed on a region not etched such as the protrusion 20b.

As shown in FIG. 4, the preliminary laminated body 24 is passed through the tip of a stamping tool (such as a punch) 30 having an annular press surface through an opening 22 c provided in the valve stopper 22 of the suction valve 26 from above, and a valve plate 14 is pressed (stamped) against the protrusion 20b of the valve seat 20 below. Similarly, the tip of the stamping tool 30 is passed through the opening 22c provided in the valve stopper 22 of the discharge valve 28 from below, and the valve plate 14 is pressed against the protrusion 20b of the valve seat 20 thereon. As a result, the familiarity between the valve plate 14 and the protrusion 20b is improved, and the sealing performance when the valve is closed can be improved.

  2-4, the code | symbol 32 is a base board. The base plate 32 is a stainless steel plate having a thickness of 0.5 mm, for example, and includes a flow path 32a facing the valve seat 20 (opening 20a) of the suction valve 26 and a valve stopper 22 (flow path 22b) of the discharge valve 28. And a flow path 32b opposite to each other. These flow paths 32 a and 32 b are laminated on the lower surface of the preliminary laminated body 24.

A frame 34 has the same outer shape as the base plate 32 and is formed by punching a rectangular opening 34a on the inner side of a predetermined width from the outer peripheral edge of a stainless thin plate having a thickness of 0.02 mm. The opening 34 a surrounds the suction valve 26 and the discharge valve 28. Reference numeral 36 denotes a diaphragm, which is a thin stainless steel plate having a thickness of 0.05 mm. This also has the same outer shape as the base plate 32. Reference numeral 38 denotes a second frame, which is a thin stainless steel plate having a thickness of 0.04 mm. The outer shape of the second frame 38 is the same as that of the base plate 32.

  The preliminary laminate 24 has a base plate 32 on the lower surface and a frame 34, a diaphragm 36, and a second frame 38 sequentially stacked on the upper surface, and are multilayered and joined while being pressurized. For example, diffusion bonding is performed. As a result, a diaphragm chamber (pressure chamber) 40 is formed between the diaphragm 36 and the upper valve seat 18 facing the diaphragm 36.

  After the multi-layered joining of a large number of thin metal plates is performed as described above, the sheet-like PZT 42 is attached to the diaphragm 36 from the right side of the second frame 38. If this PZT 42 is not polarized, it is polarized in an electric field. The wiring connected to the electrode of the PZT 42 is guided upward and connected to a drive circuit (not shown).

  In this embodiment, the flow paths 32a and 32b of the base plate 32 are connected to a fluid supply path and a discharge path (both not shown), respectively, and the drive circuit of the PZT 42 is operated for use. The diaphragm 36 vibrates up and down by the operation of the PZT 42, and the volume of the diaphragm chamber 40 is changed by this vibration. When the diaphragm chamber 40 has a negative pressure due to this vibration, the valve plate 14 of the suction valve 26 moves away from the valve seat 20 and the suction valve 26 opens, and the valve plate 14 of the discharge valve 28 contacts the valve seat 20 and the discharge valve 28 closes. As a result, new fluid is sucked from the suction valve 26. When the diaphragm 36 pressurizes the diaphragm chamber 40, the suction valve 26 is closed, the discharge valve 28 is opened, and the fluid is discharged from the diaphragm chamber 40 through the discharge valve 28.

DESCRIPTION OF SYMBOLS 10 Micro diaphragm pump 12 Valve plate sheet 14 Valve plate 14a Valve plate opening 14b Support arm 16 Flow path opening 18 Valve seat sheet 20 Valve seat 20a Opening 20b Projection 20c Half etching range 22 Valve stopper 22a Annular part 22b Flow path 22c Opening 24 Preliminary laminated body 26 Suction valve 28 Discharge valve 30 Stamping tool 32 Base plate 34 Frame body 36 Diaphragm 38 Second frame body 40 Diaphragm chamber 42 Drive element (piezo element, PZT)

Claims (11)

A micro diaphragm pump having a diaphragm chamber in contact with one side of an intake valve and a discharge valve,
Two valve plate sheets in which one valve plate of the suction valve and the discharge valve and a flow channel opening serving as a flow channel of the other valve are formed and are stacked in a direction in which the valve plate and the flow channel opening face each other When,
Two valve seats formed on both sides of this laminate, a valve seat facing the valve plate of the one valve plate sheet and a valve stopper facing the valve plate of the other valve plate sheet,
A base plate overlaid on one valve seat seat and having two flow passages respectively communicating with the suction valve and the discharge valve;
A frame that is superimposed on the periphery of the other valve seat and surrounds the suction valve and the discharge valve;
A diaphragm that forms a diaphragm chamber between the frame body and the valve seat that overlaps the frame body;
A driving element held in the diaphragm;
A micro-diaphragm pump comprising:   2. The two valve plate sheets and the two valve seat sheets are formed of a thin metal plate, and the two valve plate sheets are multilayered and joined by sandwiching the two valve plate sheets between the two valve seat sheets. Micro diaphragm pump.   The valve plate is held by a support arm extending from the inner edge of the valve plate opening formed in the valve plate sheet to the inner diameter side, and serves as a flow channel opening formed in the valve plate sheet and a flow path for the discharge valve formed in the base plate The micro diaphragm pump according to claim 1, wherein an opening diameter of the opening is equal to an inner diameter of the valve plate opening.   2. The micro diaphragm pump according to claim 1, wherein the valve plate and flow path opening of the valve plate sheet and the valve seat and valve stopper of the valve seat sheet are processed by either etching or press punching.   The frame and the diaphragm are thin metal plates, which are laminated on one side of the laminate formed in claim 2, and a base plate is laminated on the other side of the laminate, respectively, and multilayered and joined. 2 micro diaphragm pump.   The micro-diaphragm pump according to claim 1, wherein the valve seat formed on the two valve seats is formed with an annular ridge facing the valve plate to improve sealing performance with the valve plate.   The micro-diaphragm pump according to claim 6, wherein a DLC film is formed on the annular ridge formed on the two valve seat sheets, and the ridge is cured and smoothed.   8. The micro-diaphragm pump according to claim 7, wherein the valve plates of the two valve plate sheets are stamped to press the annular protrusions of the valve seat sheet to improve the adhesion with the protrusions.   The valve stopper of the valve seat includes an annular portion facing a protrusion formed on the valve seat of another valve seat, and a flow passage divided in the circumferential direction around the annular portion, 9. The micro diaphragm pump according to claim 8, wherein a stamping tool can be inserted.   2. The micro diaphragm pump according to claim 1, wherein the driving element is a piezo element attached to the diaphragm.   The micro-diaphragm pump according to claim 10, wherein a second frame body surrounding the piezoelectric element is fixed to the diaphragm.

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